Continued Development of a Photochemical Model and Application to the Southern California Air Quality Study (SCAQS) Intensive Monitoring Periods: Phase 1.

摘要

Air quality models describe the physical and chemical processes determining the dynamics of pollutants in the atmosphere. These models are the most scientifically sound foundation for quantifying how changes in emissions will affect future air quality. One model designed for both these purposes is the CIT model. The CIT model is an advanced, state-of-the-science, three dimensional photochemical air quality model. As part of the project, extensive effort has been devoted to further enhancing the model, including coalescing efforts from previous projects and updating and improving the code structure. The efforts have resulted in a single model with an advanced chemical mechanism (LCC) and deposition routine (resistance model), that is relatively easy to use and modify. A second purpose of the study was to apply the CIT model using data obtained during the Southern California Air Quality Study (SCAQS). SCAQS was an extensive field study designed to collect the necessary data for evaluating air quality models. Model results were compared against observations of ozone, NO2, CO, organics and PAN, during the 27-29 August 1987 intensive measurement period. Results of the model application showed good performance at the Western and Central Air Basin sites, and that the comparison of predictions and observations at Eastern Valley sites gave further evidence that the organic emissions are significantly underestimated.